The Science Of Grilling
    By Hank Campbell | May 30th 2010 12:42 PM | 25 comments | Print | E-mail | Track Comments
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    Cooks want to tell you grilling is an art or a craft.   We know better.  Grilling, like anything worth doing, is a science.   Anything that has been around for a million years is a science and fire has been considered by millenia as the thing that put humans on the map so nothing is more fundamental to anthropology, evolution and archeology than man, meat and fire.

    But science is not always simple and that is why some think they can't grill so they have to call it an art instead.    Grilling is easy when you have a science mentality.   You just need to quantify it.  If you're new to grilling there are some obvious things to do, like control the variables.    In the case of meat, for example, make the pieces as uniform as possible when you are new.  And if you aren't cooking meat, why are you reading this article?(1)   Otherwise, it really doesn't matter how much art you have in you, and you don't need temperature gauges or manuals, just some basic knowledge.

    In grilling, chemistry makes biology better

    Meat is muscle from delicious animals and is about 75% water, 20% protein, and 5% fat and carbohydrates.   Each muscle cell has filaments made of two proteins: actin and myosin.

    Meat proteins are made up of amino acids which may be charged and adding salt ions can  increase the water-holding capacity of your non-vegetarian treats. The salt moves into the meat and extra water is also absorbed so on your grill the meat holds on to the moisture, which means you get juicier stuff.   Yep, it's plain old osmosis, lower concentration to higher through a semipermeable membrane.   In meat, this is the plasma membrane that surrounds the individual cells.

    Basically, the individual protein molecules in raw meat are in coils and when meat is heated, the bonds break and the protein molecule unwinds.  Heat will also shrink the muscle fibers as water is squeezed out and the protein molecules recombine so a brine will help reduce that.

    Meat fibers before and after cooking.   Micrograph images courtesy Nutrition and Food Management, Oregon State University

    Give it a try.  Make a salt brine, one cup of salt per gallon of water, and soak some chicken in it for a few hours.    Worried about too much salt?  Don't be.  I am not sure you can oversalt meat before cooking, and I have really tried.   And I rarely salt my food post-cooking so it isn't like I have a taste for it.

    Gas versus charcoal - it's all physics

    There are elitists in science, in tea houses and in grilling.   Elitists in grilling will insist charcoal(2) is superior, and can even identify various types of wood.  I can't dispute that because if you are the Joe DiMaggio of grilling you might be able to consistently tell the difference but with identical cuts and recipes most people cannot tell.   Part of it is showmanship.   If you are hanging out with people and you want to talk, go charcoal.   For just the family, use the grill.

    Some purists prefer charcoal because you can move the heat pretty easily but I have a four-burner grill so that isn't a problem.   If you are buying a grill, getting something with 2 or more burners gives you a lot more flexibility.

    Direct versus indirect heat

    There are only two things to keep in mind with grilling; time and type of heat.   Both of those things have a rule of thumb based on meat.    For ribs and roasts, as an example, you need to use indirect heat because they will cook slowly but for hamburgers you want direct heat.    

    Who does it matter?   In science, it's the Maillard reaction, after the French physician and chemist Louis Camille Maillard, who discovered the link when he heated sugars and amino acids together and the mixture slowly turned brown. but it's just called browning to grillmasters (3).   Chemically, the denatured proteins on the surface of the meat recombine with the sugars present during cooking.     When you grill, the outside temperature is higher than the inside, triggering the Maillard reaction and creating stronger flavors on the surface.  

    It also reaffirms why brining will help you get a better flavor - in brining, the meat's cell fluids are less concentrated than the salt water so water flows out of the meat cells and salt flows in. The salt then dissolves the fiber proteins and the meat's cell fluids become more concentrated,  drawing water back in. With more salt and water in the cells, when the meat is cooked and water is squeezed out, there is still water left because water was added before cooking.

    You may note by now that I don't get into fat here though it is essential in flavor but there are 600 components in just the aroma of beef alone so getting into fat and figuring out fat levels from animal to animal and then part to part would be too much for a rule of thumb.   What is not essential for grilling but interesting to know is that the flavor-carrying molecules in meat are hydrophobic - repelled by water.    And meat is 75% water but flavor-carrying molecules dissolve in fat and when that fat is heated, it melts and 'lubricates' the muscle fibers in the meat, helping to keep it juicy.  So you use that to your benefit here even without us getting too far into it.

    Cooking times - the short version

    Make sure your grill is hot.  You don't need anything more than your hand.  If you can't hold your hand over the grill for more than two seconds, it is hot, around 450 degrees.  If you can last 5 to 6 seconds, the grill is about 250 degrees.

    If you are cooking some things with indirect heat, move the coals to one side of the grill and cover it or shut off a burner in one side of the grill and cover it.   Using the handy times below it is easy to plan so that all of the meat is finished together.

    For hamburgers, if you have no timer, you need about 5 minutes on each side over direct heat, as hot as you want.   How long is that?  If a football game is on, and it's not the last two minutes, that will be 6 plays and a commercial break and you can adjust those ratios accordingly for other things below.   If you have a timer, set it to 4.5 minutes for each side.    If you have some Pabst Blue Ribbon laying around, pour a little on your personal burger.

    For kabobs, 10-12 minutes total, depending on how well done you like the meat.   If you have some Pabst Blue Ribbon laying around, pour a little on your personal kabob.

    For decent sized steaks, 8 - 14 minutes for medium rare, 12 - 18 minutes for medium.  As above, you flip once.   If you have some Pabst Blue Ribbon laying around, pour a little on your personal steak.  If your steaks still have a bone in, subtract one minute.

    For hot dogs, 8 minutes, but you can turn them as often as you want while you drink that Pabst Blue Ribbon.    Sausages too, but cook them in a skillet in that PBR first, then finish them on the grill.  Dogs and sausages are great for the social aspects of grilling because it gives you something to do with your hands while you discuss Euclidean geometry.

    Chicken breasts without the bone are pretty quick but the temperature you use for steaks and burgers will be too high, so here you might want to go indirect if you are also cooking burgers.  8 - 12 minutes, turning once, and juice will run clear when they are ready.    

    Kim also likes it when I use any old chicken legs with some olive oil on the surface and a rub or salt applied and I cook them for 25 minutes on each side using indirect heat.  You can cook those in 35 minutes total if you like but they won't be as awesome as mine.

    Ribs are 1-1/2 to 2 hours over indirect heat.   Baste with any tomato-based recipe you like, almost anything sweet will make you happy, but only during the last 20 minutes, no matter what you read elsewhere, unless you know what you are doing.  Waiting until near the end adds flavor and will keep the sauce from burning.

    Barbecue sauce from stuff you have laying around:

    1/3 cup soy sauce
    1/2 cup water
    Small amount of onions and garlic or onion and garlic powder
    1/4 cup ketchup
    1/4 cup corn syrup
    1/4 cup honey

    A teaspoon of liquid hickory smoke seasoning if you have it, and then you can tell people you made sweet hickory barbecue sauce for them.

    Did I miss anything?  If I am wrong on the Internet, I am sure someone will let me know.


    (1) And why do you make Veggie Burgers that taste like hamburgers if you dislike meat?

    (2) They certainly have history on their side.   Where charcoal was invented is something of a science mystery.  It's been used for at least 5,000 years but no site can establish a significantly significant first use.   Favorites are hickory, cherry, and mesquite.

    (3) The Maillard reaction is also what makes self-tanning products work.  If that doesn't creep you out, I don't know what will.


    Christina Znidarsic
    Fantastic!  I'm printing this out and using it as a reference for my summertime meat-heating shenanigans.  The PBR love is priceless.
    You're making me very, very hungry, Hank! lol ;-)

    Thanks for the barbecue sauce recipe!
    Some people are all angst-ridden about giving out secret recipes and techniques.  Not me.  Science 2.0 is all about spreading the knowledge.  So when someone tomorrow asks me about the secret to my awesome chicken I will say, "The scientific method" and they will walk away knowingly, armed with all they need.
    Since you mentioned chicken, and I'm always on the lookout for new recipes, I would love to have your recipe for chicken! lol ;-)
    No problem!  Here you go.
    Good one, Hank!

    I kind of walked into that one! ;-)

    But seriously, I do have a recipe for chicken that I learned from a college roommate. We had to be creative back then being that we were poor, starving undergrads.

    We use to buy a whole chicken and cut it up and put the pieces in a large skillet.

    We poured a quarter cup of chicken broth in the skillet with the chicken.

    We added sage, a small amount of thyme, freshly-ground black pepper, and fresh pressed garlic. Later I revised the recipe by adding Southwestern Chipotle; I developed a taste for cayenne and chili peppers when I was Tuscon, AZ. But, you don't need to add the Chipotle if you don't want.

    I can't give you the exact amounts of the herbs and spices, because I measure them intuitively in my hand. Usually two or three cloves of garlic will do. I use more sage than thyme.

    Anyway, we would cover the skillet and let it simmer for about 45 minutes or until we felt the chicken was thoroughly cooked on a medium to low heat, checking it every once in awhile in the process.

    I think it's pretty good. You might want to try it.
    The simplest recipe for chicken that I know of was written by Neil Munro under his pen-name of Hugh Foulis.

    On board the Clyde puffer Vital Spark, the crew member responsible for preparing the day's dinner reflects on an old family recipe for chicken:

    "First steal a chicken."
    , Patrick. I'll have to remember to include that the next time I give out a recipe for chicken! ;-)
    First, if PBR is not paying you, then they should because that is some awesome product placement. I don't even drink beer and your article makes me want to try some PBR while grilling as suggested.

    As for "Veggie Burgers that taste like hamburgers." I sometimes eat and have eaten veggies burgers, not because I dislike meat in any way, but because I love meat and I am just trying to do something better for my health, for longevity reasons. In terms of lifespan, I know I've already abused this body and voided the warranty many years ago, but for my daughter I am trying to do a little better each day to do my part to improve my health. I've learned that not all veggie burgers are made equal. I wish we could devote some science to improving the taste of healthy foods, while also maintaining their "healthy" status.

    Christina Znidarsic
    Definitely, Michael.  Veggie burgers can be surprisingly bad in terms of sodium content, can contain some really random filler-type stuff, and are not as nutrient-dense as people think.  If you're looking for a healthy alternative to a traditional burger, look into making and freezing your own.  I make black bean alterna-burgers that deliver a great protein whallop and are delicious to boot.
    As for "Veggie Burgers that taste like hamburgers." I sometimes eat and have eaten veggies burgers, not because I dislike meat in any way, but because I love meat and I am just trying to do something better for my health
    I wasn't asking why people eat them at all, I get why people do (and I have also) but I meant since the target market is people who do not like meat rather than meat eaters making a sporadic foray into faux vegetarian living, it seems odd to make patties that are shaped like meat, taste like meat and even have fake grill marks on them.  It just seems odd to me.
    And if you aren't cooking meat, why are you reading this article?

    I'm here because I thought 'the science of grilling' would be about psychology and the means of obtaining information from unwilling experimental subjects by the application of thermal inducements.
    Pyroboarding?!?!  That's an article that needs to be written.
    What a wonderful coinage, Hank!  I wish I'd thought of it. :-)
    Christina Znidarsic
    I would like to volunteer my services to be part of the first Pyroboarding R&D team.  Perhaps we could get a PBR sponsorship!
    Oddly, if someone asked me to do an Austin Powers-ish ridiculous level of product placement, or any at all, I would be offended.  But PBR is unfairly besmirched with no data behind the critics at all.

    Ummm, you do realize pyroboarding would not be surfing in a volcano, right?
    Christina Znidarsic
    Awwww.  I just got a new asbestos bikini too.
    Okay, it can be volcano surfing.  I think we all need to see this bikini.
    Steve Davis
    Hank, I'm sorry, but you're not the first to make a science out of grilling.
    When my wife grills me, I 'fess up quick smart!
    In my country, people like grilling however, recent studies show that especially meat which is grilled above fire can be harmful to our health. I think people should not burn meat this could prevent us some diseases like colon cancer.

    More people will die from uncooked chicken in a week than will ever die from burned chicken.
    I have never understood why veggie burgers and other products are made to look like and vaguely taste like meat.

    I like to grill veggies on the grill, but as veggies - not as fake meat - a little olive oil and balsamic vinegar - and taste explosion - try it with beets!

    When I propane grill, I add a smoker box to get rid of the gas taste - and I do prefer to use charcoal (real charwood, not those sawdust, coal dust and glue briquettes)

    I did a whole turkey for 7 hours, it blew the taste buds away

    You wrote : about 75% water, 20% protein, and 5% fat and carbohydrates. There's no carbohydrate in steak. See USDA analyses: It's for this reason that Maillard reactions only occur between the steak and the sauce's carbs.
    Liver is 8% carbs.  :)

     But I think my sentence is poorly worded regardless - you ...'ed out the muscle part of that sentence which is important.   Muscle has glycogen, a complex sugar but, yes, it gets broken down when muscle becomes plain old meat so then it is a protein and not a carb.